The present invention is directed to a strapping machine having an improved strap chute and release system. More particularly, the present invention is directed to an asymmetrical strap chute and release system to prevent debris from interfering with or damaging the strap chute and release system.
Strapping machines are in widespread use for securing straps around loads. One use for strapping machines is for loads of conglomerated objects that spontaneously yield multiple and sizable fragments. For example, bricks, cement blocks and the like can fragment (resulting in both large and small fragments) during the strapping operation. The fragments have been know to interfere with the proper operation of the strapping machine by clogging the strap chute and damaging the strap as it is pulled from the chute.
In one known strapping machine, the debris problem has been resolved by including a lower strap chute that is formed with a two-piece peaked guard that resembles a gable that covers the strap chute. The gabled structure opens as the strap is pulled from the chute between the guard sections or gates. In operation, as the strap is pulled from the chute the guard opens generally symmetrically, at the top, to allow the strap to pass. The guard gates are spring mounted so that they close once the strap had exited the chute. The chute includes openings at the bottom to allow debris to fall through so as to not interfere with operation of the chute. Such a guard design is disclosed in Powers, U.S. Pat. No. 6,990,895, which patent is commonly owned with the present application and is incorporate herein by reference.
Although this design works well, it has been found that debris can enter the guard and interfere with the chute when the guard is open. That is, it has been observed that debris fall into the guard (and thus to the chute) coincidentally with the guard opening to release the strap.
Accordingly, there is a need for an improved strap chute and release system that prevents the introduction of debris into the strap chute area. More desirably, such a system can be fitted onto existing strapping machines without excessive changes.